Wheelchair back



FIG. 1 is a back and side perspective view of the wheelchair back of the new design;

FIG. 2 is a back elevational view of the wheelchair back of the new design; and,

FIG. 3 is a side elevational view, taken along line 3-3 of FIG. 2, of the wheelchair back of the new design.

The broken lines shown in the drawings illustrate the environment of the wheelchair back and form no part of the claimed design. 

CLAIM The ornamental design for a wheelchair back, as shown and described. 